Automatic clutch



Dec. 11, 1934. w, A. HAMILTON 1,984,131

AUTOMATIC CLU'IVCH Filed May 3l, 1955 2 Sheets-Sheet 1 INVENTOR WML/A /W .Ji/W/z. rom

ATTORNEYS Dec. l1, 1934- w. A. HAMILTON AUTOMATIC LUTCH 2 Sheets-Sheet 2 Filed May 5l, 1935 ATTORNEYS Patented lec. 11i, if' K UNITED STATES PATENT OFFICE AUTOMATIC CLUTCH William A. Hamilton, Birmingham, Ala. Application May 31,1933, `serial No. 673,780

, 1 e claims. (o1. isz-105) The invention relates to improved features of pins 44. The blocks 38 are recessed at 46 for construction and arrangement hereinafter more slidable guiding engagement with the outer exspecicallydisclosed and pointed `out withv partremities of the arms 22 and 24, as shown. ticularity in the appended claims. The friction blocks are arranged to coact'with The invention will be Vfully apparent from the the inner face of the annular flange 48 of the` 5 accompanying drawings when read in connection driven member50 secured to the driven shaft l2 with the following detail description and will be by key 15. defined with particularity in accordance with the In operation, when a driving torque is applied provisions of the statutes in the appended claims. to the shaft centrifugal force will gradually lo Two alternative embodiments of the invention throw the weights 30 outwardly against the ac- A 10 are illustrated in the accompanying drawings, in tion of the springs 32.` And because of the fact whichthat this centrifugal force is transmitted through Fig. l is a face view of the clutch embodying a moment arm which measured from the'pivotal my invention, portions ,shown in the sector bepoint 26 to the line ofy force passing through the tween the dot and dash lines being shown in seocenter of gravity of the Weight 30, is materially 15 tion, the plane of section being indicated apgreater than the moment arm measured from proximatelyby the seotionline 1-1 of Fis- 2; the iulcrum 26 to the center of the pin 44, it Fig. 2 is a central longitudinal Section through follows that the net effect of the centrifugal the clutch on line 2-`2 of Fig. l; force exerted by each weight 30 is materially in- Fig. 3 iS a VieW Similar to Fig. l showing the creased so as to firmly hold each friction block 20 Darts in thepOSitiOn that they assume When the inengageinent with the surface 48 of the driven Clnteh iS rotating at a relatively high Speed; member.' And inasmuch as centrifugalV force Figl iS a VieW taken aDDrOXmately 0n the exerted by a revolving member increasesin prostaggered section line 4 4 of Fig. 3; portion to the speed of rotation, it follows that Fig. 5 is a view in longitudinal section on line the higher the speed of the shaft the greater 2 5-5 0f Fig. 6, illustrating the inVentiOn aS aD- will be the friction grip between the friction plied to a pulley; blocks and the driven member. The arrange- Fig. 6 is a View from the left end of Fig. 5, with merit is such that as the speed of the drive shaft one of the end members broken away t0 reveal starts from zero and at no load and gradually the interior parts. picks up speed so also will friction between the 30 Referring rst to Figs. l to 4 inclusive, the deblocks and the driven member increase, thus ViCe illustrated may be regarded as a shaft couthere will be a gradual and smooth picking up plns Comprising a driving shaft l0 and a driven of the load by the gradually increasing friction shaft l2 adapted to be operatively connected with between the blocks 38 and the annular flange 48 one another by the Clutch 0f Iny invention When of the driven member. And when the drive shaft 35 the driving Shaft 10 reaCheS a predetermined reaches a predetermined maximum speed the speed. The driving shaft carries two main drivcentrifugal force acting through the lever arms ing members 14 and 16, the fermer being driven will exert such a great pressure that there will by the Shaft through a key l8- The members 14 be no slippage and the driving. and driven memand 16 are keyed together at their hub portions bers will, therefore, both revolve as a unit, 40 by key 20, hence they both revolve as a unit with In the modification of Figs. 5 and e, the inthe drive shaft. Outwardly extending arms 22 vention is embodied in a pulley. In this modifiand 24 carried by the members 14 and 16, recation, the pulley rim 52 is a driven member. It spectively, carry pins 26 which form pivotal supis supported by end plates 54 having hubs 56 ports for the arms 28 of Weight elements 3G, which are rotatably mounted on collars 58 se- 45 which are adapted to be thrown out by Centrifugal cured to and movable with a driving member 14a force against the action of Springs 32. The secured to a drive shaft 10a and driven through springs, as clearly shown, have hook portions a key 18a. The member 14a has arms 22*1 and 24a which engage pins 34 carried by the weight memcorresponding substantially to the similar parts bers and are anchored to clips 36 secured to the shown in Figs. 1 to 3 inclusive. These arms 50 end face of the member 16. pivotally support weight members 30a which Friction blocks 38, carrying suitable friction transmit centrifugal force through multiplying linings 40, are provided with bifurcated lugs 42 lever arms to the friction blocks 38a coacting which straddle the arms 28 of the weighted elewith the inner surface 48e of the pulley rim 52.

ments 30 and are pivotally connected thereto by With such an arrangement, it will be appreciated 55 that upon the application of a torque to the shaft 10a, when the shaft reaches a predetermined speed centrifugal force acting through the weights a and friction blocks 38a will gradually and positively apply the driving torque to the pulley. Of course when the speed reaches a desired predetermined number of revolutions per minute it will be understood that there will be no slippage between the friction blocks and the pulley and thus the shaft and the pulley will rotate in unison.

From the foregoing, it will be manifest that in both of the embodiments of the invention illustrated, because of the mechanical advantage secured by transmitting centrifugal force through the moment arms of different lengths, I will for a given unit of weight of centrifugal member secure a greater friction grip than would otherwise be possible. This results in a saving of the over-all weight for a clutch to transmit a given torque at a given speed and hence results in a corresponding saving in power due to a lessening of the dead weight carried by the power shaft.

Another advantage, which accrues from the use of my invention, is the ease of changing from one driving source to another driving source in the operation of centrifugal pumps, fans and like rotary devices which are provided with dual drives. For example, if, as in the case of interruption of electric power current, a motor connected to a fan shaft coupling, such as illustrated in Figs. 1 to 4 inclusive, should slow down, the clutch would then automatically and gradually release. It is then but a simple matter for an operator to start an engine at the other end of the fan shaft connected thereto by one of my improved couplings because, when the engine attains the requisite speed, the friction blocks in the coupling will automatically be forced outwardly, as herein described, so as to operatively connect such engine with the fan, hence little or no fan operating time is lost.

While I have described quite specifically the design and arrangement of the embodiments of the invention herein illustrated it is to be understood that various modifications and substitutions of equivalents may be made by those skilled in the art without departing from the invention as defined in the appended claims.

What I claim is:- x

l. Clutch mechanism comprising rotary driv`,

ing and driven members, the driving member having a plurality of pairs of outwardly Yextending drive arms, friction blocks adapted for coupling the two members, said blocks having pockets slidably engaging the extremities of said arms, weights having portions extending between each pair of arms and pivoted thereto and operatively connected with said friction blocks, the connection between the weights and the blocks being so arranged that the eiTect of centrifugal force on the weights is transmitted to the blocks with increased magnitude. l

2. The clutch mechanism of claim 1, including detachable spring anchorages secured to the drive member and springs coacting therewith and with said weights tending to urge the latter toward the center of rotation of the drive member.

3. Clutch mechanism of the character described comprising a driven member, a rotary drive member including .a pair of complementary parts having telescopically engaging hub portions, means preventing relative motion between said parts, respective arms fixedly secured to said hub portions and extending outwardly therefrom, friction blocks having substantially radial inwardly opening guide pockets slidingly engaging the outer extremities of said arms and having inwardly extending lugs straddled by said arms, weights having Shanks fulcrumed on said arms and carrying pins constituting oating pivotal supports for said friction blocks.

WILLIAM A. HAMILTON, 

